Arrangement at telescopic lifting beam

ABSTRACT

Two telescopic lifting beams are loaded in their protruded position and are driven from a retracted position to a protruded position. In order to improve the bending strength of the lifting beams, the lifting beams are surrounded by two telescopic tubes, one of the tubes being fixed to the outer end of the telescopic first lifting beam and is slideable on the second telescopic tube, which extends inwardly on the second lifting beam.

FIELD OF THE INVENTION

This invention relates to an arrangement at at least two telescopicallyprotrudable lifting beams, which are loaded in their protruded positionand which are driven in an optional way from a retracted position to aprotruded position.

BACKGROUND OF THE INVENTION

Lifting beams of this type are used, e.g. within the medical service forlifting means, when a person is being lifted from a sitting position toa standing position or from one place to another. Telescopic liftingbeams of this kind are also used for other lifting purposes forpatients.

The lifting beams are normally loaded in their longitudinal directionand they are designed to meet such a load. The lifting beams can bedriven hydraulically via gears or manually using rope-driving means orwith the help of a crank means.

SUMMARY OF THE INVENTION

It has now shown, e.g. within the medical service, that the liftingbeams unintentionally have been loaded by bending when the telescopicbeams are in their protruded position in relation to each other, whichhave lead to that the outer lifting beam has been bent in the area whereit protrudes out of the outer end of the first lifting beam. The objectof the invention is to increase the strength of the lifting beams whenthey are in their protruded position and that this is accomplished bysimple means, which are cheap. The reinforcement is easy to apply onexisting lifting beams without any complicated amendments of theirdesign.

In order to reach this object the invention has been given thecharacteristics, which are stated in the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described by reference to thedrawings.

FIG. 1 is hereby a side view, partly in a longitudinal section, of twotelescopic lifting beams in their protruded position.

FIG. 2 is partly a longitudinal section of the telescopic beams in theirretracted position.

FIG. 3 is a longitudinal section of an area depicted by the arrow A inFIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The arrangement shown in FIGS. 1 and 2 comprises a first lifting beam 1,which is telescoping in a second lifting beam 2, being fixed to adriving means 3 which displaces the first lifting beam 1. The drivingmeans 3 can be any known engine as e.g. a hydraulic engine or a gearmotor, which drives the lifting beam 1 telescoping in the lifting beam2. The lifting beams are loaded when the lifting beam 1 is protrudingout of the lifting beam 2 in the position shown in FIG. 1. The liftingbeams 1 and 2 are surrounded by two telescopic tubes 4 and 5, the firsttelescopic tube being displaceable over the second telescopic tube 5.FIG. 1 shows that the telescopic tubes 4 and 5 are in their mostprotruded position while FIG. 2 shows that the telescopic tube 4 isretracted on the second telescopic tube 5 over half of the length of thesecond telescopic tube 5. The first telescopic tube 4 is fixed to theouter end 6 of the first lifting beam 1 by an attachment 7. Thetelescopic tube 4 has a first coupling part 8 at its inner end, see FIG.3. The second telescopic tube 5 has a second coupling part 9 at itsouter end, see FIG. 3. The two coupling parts 8 and 9 work in such a waythat when the telescopic tube 4 is moving with the telescoping beam 1,the coupling part 8 is hitched by the coupling part 9 so that the secondtelescopic tube 5 follows the first telescopic tube 4. When thetelescopic tube 4 moves in the opposite direction, the coupling part 8moves away from the coupling part 9 and the second telescopic tube 5 ispushed inwards on the second lifting beam 2 by that the attachment means7 will abut the outer end of the second telescopic tube, see FIG. 3.

As can be seen from FIG. 3 there is a bearing ring 10 attached to theouter end of the second telescopic tube 5. The inner periphery of thisbearing ring contacts the outside of the first lifting beam 1 and slidesalong the lifting beam 1. By this, the outer end of the secondtelescopic tube 5 is supported by the lifting beam 1. The lifting beam 2has a bearing tube 11 at its outer end, the second telescopic tube 5slides on the bearing tube 11. The second telescopic tube 5 has abearing ring 12 at its inner end, which bearing ring slides with itsinner periphery edge on the lifting beam 2. When the second telescopictube 5 is in its protruded position according to FIG. 1, the telescopictube 5 is stopped by a stop-ring 13, which is attached to the liftingbeam 2. The stop ring may also serve as a guiding means for the secondtelescopic tube 5.

When the arrangement is in the position shown in FIG. 1, the secondtelescopic tube 5 will act as a support for the lifting beam 1 via threepoints. The first support point is in the area shown by arrow A, thesecond support point is in the area of the bearing tube 11 and the thirdsupport point is at the area of the second bearing ring 12. By this thelifting beam 1 will be reinforced against bending in the area of thetube 11.

The invention has been described above in connection with two telescopiclifting beams but the same reinforcement means can be arranged for e.g.three telescopic lifting beams. Further, there is a possibility to makethe telescopic tube 5 sliding on the lifting beam 2 along its completelength, thus without the second bearing ring 12 and the tube 11, whichmeans that according to FIG. 1 the telescopic tube slides with half ofits length on the lifting beam 2. FIG. 1 also shows that the length ofthe first telescopic tube is about half the length of the first liftingbeam in its protruded position while the second telescopic tube 5 has alength which corresponds to about half of the length of the secondlifting beam 2. The length of the telescopic tubes may of course bearranged to what is needed but the important thing is that the secondtelescopic tube is of such a length that it supports the outer liftingbeam at a point which is far away from the outer end of the innerlifting beam 2.

1. A lifting apparatus comprising a first lifting beam, said firstlifting beam being telescopable in a second lifting beam and being fixedto a driving means for driving said first lifting beam to and fro inrelation to and inside said second lifting beam by being displaced froma retracted position to a protruded position by said driving means, saidfirst lifting beam and said second lifting beam being surrounded by twotelescopic tubes, an outer one of said two telescopic tubes being fixedto an outer end of said first lifting beam and telescoping over an innerone of said two telescopic tubes, which extends slidingly telescopicallyover said first lifting beam, a coupling between said two telescopictubes consisting of a first part at an inner end of said outer tube anda second part at an outer end of said inner tube, said two parts beingengaged when said tubes are drawn apart and are disengaged when saidouter tube is retracted on said inner tube, and a bearing tube attachedat the outer end of said second lifting beam on which said bearing tubesaid inner telescopic tube slides, a length of said outer tubecorresponding to about half a length of said first lifting beam and alength of said inner tube is of such a length that said inner tubesupports said first lifting beam at a point which is at a distance fromthe outer end of the second lifting beam when the first lifting beam isin a most protruded position.
 2. Lifting apparatus according to claim 1,further comprising a bearing ring fixed to an inner end of said innertube and sliding on said second lifting beam and forming a first part ofanother coupling, which limits displacement of said inner tube outwardson said second lifting beam by the bearing ring striking against a stopring attached to the second lifting beam.